Oil heater for hot-water furnaces



June 28, 1949; J. CRADDQCK 2,474,574

OIL HEATER FOR HOT WATER FURNACES Filed 001:. 7, 1946 O C) C O (3 Patented June 28, 1949 UNITED STATES PATENT OFFICE 2,474,574 OIL HEATER FOR HOT-WATER FURNACES James E. Craddock, Richmond, Va. Application October 7, 1946, Serial No. 701,813

2 Claims.

The invention relates to oil heaters for coal furnaces.

An object of the present invention is to improve the construction of oil heaters for coal furnaces and to provide a simple practical and comparatively inexpensive oil heater adapted to be readily installed in coal furnaces and which will not require a pump or injector.

Another object of the invention is to provide an oil heater of this character adapted to be supplied with gas from a carburetor and possessing all of the advantages of safety and convenience of adjustment afforded by a carburetor fed by gravity or other means and located exteriorly of a coal furnace.

Another object of the invention is to provide an oil heater adapted to be readily ignited with safety by simply dropping a lighted match into the heater.

Another object of the invention is to provide an oil heater adapted to furnace a maximum amount of heat and which, after being lighted, will not require further attention other than adjustment of the carburetor for obtaining the desired amount of heat and which, should the fire become extinguished, will automatically cut off the flow of gas to the heater by the accumulation of liquid within the heater.

A further object of the invention is to provide an oil heater adapted to receive the hot water coils of a coal furnace and capable of efliciently heating water in said coils without materially affecting the heating of the coal furnace or otherwise impairing its efficiency.

With these and other objects in view, the invention consists in the construction and novel combination and arrangement of parts hereinafter fully described, illustrated in the accompanying drawings and pointed out in the claims hereto appended, it being understood that various changes in the form, proportions, and minor details of construction, within the scope of the claims, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings- Figure 1 is a front elevation of a coal furnace provided with an oil heater constructed in accordance with this invention, parts of the oil heater being illustrated in dotted lines;

Figure 2 is a vertical sectional view taken substantially on the line 2-2 of Figure 1;

Figure 3 is a plan view of the oil heater, the coal furnace being illustrated in section;

Figure 4 is a sectional view taken on the line 4-4 of Figure 2;

Figure 5 is an exploded view of the heater cas- In the accompanying drawings, in which is illustrated the preferred embodiment of the invention,,the oil heater comprises a casing l constructed of suitable metal and open at the top and composed of vertical front and rear walls 2 and 3 and side or end walls 4 and provided with a horizontal bottom 5, and the casing, which may be constructed of sheet metal or composed of a casting, is arranged within the fire pot 6 of a, coal furnace I which has its grate 8 sealed by a metal plate 9 and a layer ill of cement or other suitable plastic material or any other fireproof substance. The plate 9 may be constructed of sheet metal and it preferably covers the entire grate and conforms to the configuration of the coal furnace and is supported by the grate as clearly illustrated in Figure 2 of the drawings.

The heater casing is rigidly secured in position by means of a plurality of depending bolts II preferably spot welded at their heads to the lower face of the bottom 5 and extending through the layer ID, the metal plate 9 and the grate 8 and provided at their lower threaded portions with nuts l2, but the bolts may be mounted in any other desired manner.

The rear wall 3 is provided at its upper portion with an opening [3 consisting of a vertical slot extending downwardly from the upper edge of the rear wall and terminating short of the bottom of the casing to permit pipes l4 and l5 of a hot water coil IE to pass through the rear wall to the interior of the heater casing. The rear wall is completed by a vertical closure plate or section I! which may be secured to the rear wall 3 in any suitable manner and it is provided with a slot l8 extending upwardly from the lower edge of the closure plate to permit it to straddle the pipes 14 and I5. The opening I3 and the separate detachable rear wall section I! enable the heater casing to be readily placed in position within the coal furnace.

The bottom of the heater casing is provided with an upwardly extending tubular air inlet [9 and the front wall 2 of the casing is provided at its lower portion with a horizontally projecting nipple 20 which is connected by a suitable coupling 2| with a pipe 22 extending from the heater casing through the front of the furnace I and threaded at its outer end for the attachment of a carburetor 23. The carburetor, which may be of any preferred construction, may have any other suitable pipe connection with the heater casing and it will be provided with the usual adjusting means for controlling the flow of hydrocarbon gas through the pipe 22 for regulating the flame and the heating capacity of the oil heater. The carburetor may be supplied with oil from any suitable source and by a gravity or other feed and the carbureted air or hydrocarbon gas entering the heater casing is ignited and. mixes with air passing upwardly through the central air inlet 89 to form a combustible mixture.

The coal furnace is provided with the usual upper fuel door 24 and the lower ash pit door 25 provided with a suitable damper means for controlling the entrance of air to the furnace above and below the grate. The heater casing is provided at the upper portion of its front wall with a door 26 hinged at the lower edge at 27 to the front wall which is provided with a door opening 28, as clearly illustrated in Figure of the drawings. The door 23 has a suitable knob or handle 29 to enable it to be opened and closed and if desired any suitable means may be provided for securing the hinged door 28 in its closed position. Also the door 28 may be provided with a transparent window 30 for enabling the flame within the heater casing to be readily observed without opening the door 28. The gaseous fuel within the heater may be readily ignited by opening the door 28 and dropping a lighted match within the heater.

The hydrocarbon gas supplied to the heater casing by the carburetor and entering the heater casing at the bottom thereof is directed inwardly towards the center of the casing by means of upper and lower ballle members 3i and 32. The heater casing, while preferably rectangular in horizontal section, may be of any other desired configuration and, as clearly illustrated in Figure 5 of the drawings, it is provided on its interior with upper and lower lugs 33 and 34 preferably located at the corners of the rectangular heater casing and forming supports for the baffles 3| and 32 which are rectangular. The baffles 3| and 32 may be constructed of sheet metal or any other suitable material and they are provided centrally of their rear portions with slots 35 and 36 to permit them to straddle the pipes l4 and I5 in assembling the bafiles within the heater casing and also in removing them therefrom should the same be'necessary.

The centrally arranged tubular inlet 19 which extends upwardly from a central opening in the bottom 5 of the heater casing is of sufficient height to permit a large enough quantity of liquid to accumulate Within the bottom portion of the heater casing to cut off the flow of fuel from the carburetor should the heater, after being lighted, become extinguished.

When gaseous fuel is admitted to the lower portion of the heater casing and ignited, the flame, products of combustion and any unconsumed fuel pass upwardly and are directed inwardly by the baffles towards the air entering the tubular centrally arranged air inlet so that there is a thorough comi'ngl-ing of the air with the fuel and products of combustion. A substantially complete combustion of all fuel is thereby efiected and a maximum amount of heat is obtained from such fuel. Air is admitted from the ash pit of the furnace to the tubular air inlet I9 through an opening 37 extending through the grate 8, the plate 9 and the plastic layer I0.

I claim:

1. A coal furnace heater including a casing open at the top and composed of vertical front, rear and side walls and provided with a horizontal bottom adapted to be supported upon the grate of a coal furnace, the rear wall being provided with a vertical slot extending downwardl from the upper edge of said rear wall and terminating short of the bottom of the casing and arranged to receive the pipes of a water heating coil, a vertical closure plate fitted against the rear wall of the casing and provided with a vertical slot extending upwardly from the lower edge ofthe closure plate and arranged to permit the same to straddle said pipes and close the vertical slot of said rear Wall above said pipes, upper and lower baflles, removably supported within the casing and having openings of a size to receive said coils and provided with slots aligned with the slot of the rear wall of said casing and of a size to clear said pipes in assembling and: installing the heater, a fluid fuel inlet at one of the wallsof the casing. adjacent the bottomv thereof, and an air inlet tube extending upwardly from the bottom: of the casing and having its upper end-located: at an. elevation above that of the fuel inlet.

2. A coal furnace heater including a casing openat the top and composed of vertical front, rear and side walls and-provided with a horizontal bottom adapted to be supported upon the grate ofacoalz'furnace, the rear wall being provided with. a vertical slot extending downwardly from the :upper edge of said rear wall and terminating short of the bottom of the casing and arrangedxtoreceive the pipes of a water heating coil, a vertical closure plate fittedagainst the rear wall of? the casing and provided with a vertical slot extending upwardly from the lower edge of they closure plate and, arranged: to: permit the same to straddle; said: pipes. and close: the vertical slot 'of said rear wall above said pipes, upper and lower bafiiesremovably supported within the casing and having openings of a size to receive said coils :and' provided with: slots, aligned with the slot of the rear wall of said casing and of a size to clear saidpipes in. assembling and installing the heater, fastening devises connected with and depending from the bottom of the casingv and arranged to extend between thegrate bars of the furnacefor securing; the casing in position, a fluid fuel; inlet at onevof, the walls of the casing adjacent the bottom. thereof, and an air inlet tube extending upwardly from the bottom of the casing and having'its upper end located at an elevationabove that of the fuel inlet.

JAMES E. CRADDOCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name. Date 1,017,321 Rogers Feb. 13, 1912 1,379,233 Wilke May 24, 1921 2,010,920 Karsel Aug. 13, 1935 2,293,697 Chadwick Aug. 25, 1942 2,302,287 Behrendt Nov; 17, 1942 2,395,765 Schneider Feb. 26, 1946 

